Syndactyly is a complete or partial fusion of adjacent fingers or toes. It is observed as a genetically heterogeneous independent disease or as a component of hereditary syndromes. Depending on the degree of involvement of the tissues of the fingers, the following types of syndactyly are distinguished:

    • Cutaneous – with the presence of a thick bridge, consisting of skin and underlying soft tissues, more often along the entire length of the fingers
    • Cutaneous membranous – often incomplete, with the presence of a thin skin membrane
    • Terminal – only at the level of the terminal phalanges
    • Bone – the bones of the phalanges of the fingers are fused. Genetic types
    • Type I (* 185900, zygodactyly.ZD Clinically: syndactyly, complete or partial membranous III and IV fingers, fusion of distal phalanges, complete or partial syndactyly II and

III toes

    • Type II (#186000, 2q31-q32, HOXD13 gene defect [142989], R). Clinically: syndactyly complete or partial III and

IV fingers of the hand, doubling of all components or part of the IV finger involved in syndactyly, polydactyly of the little toe involved in syndactyly of the IV and V toes, hypoplasia of the middle phalanges of the toes, anomalies of plantar dermatoglyphics

    • Type III (186100, 6q22-q24, damage to the SDTY3 gene [ODDD, ODOD], R) is a mutation in the oculo-dental-digital dysplasia gene locus (164200). Clinically: complete syndactyly of the IV and V fingers, sometimes with fusion of the bones of the distal phalanges, shortening of the little finger with the absence or hypoplasia of the middle phalanx, feet are not affected
    • Type IV (Chaos syndactyly, 186200, R). Clinically: complete syndactyly, polydactyly, cup hand, partial proximal cutaneous syndactyly of the II and III toes, absence of the tibia
    • Type V (*186300, R). Clinically: syndactyly with fusion of metacarpus and metatarsus
    • Polyphalangeal syndrome with syndactyly type I (* 190605, 9J) – three-phalangeal finger I, syndactyly of other fingers.

See also Acrocephalostdactyly


    • Q70 Syndactyly
    • Q70.0 Fusion of fingers
    • Q70.1

Webbed fingers

    • Q70.2 Fusion of toes
    • Q70.3 Webbed toes
    • Q70.4 Polysyndactyly
    • Q70.9 Syndactyly, unspecified

MIM. Syndactyly:

    • type I (185900)
    • type II (186000)
    • type III


  • type IV (186200)
  • type V (186300)

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